What does the acronym "V1" refer to during takeoff?

V1 is a critical speed during the takeoff phase of a flight, signifying the point at which the pilot must make an important decision: whether to continue with the takeoff or abort it. If an emergency occurs or a problem with the aircraft arises before reaching this speed, the pilot can safely bring the aircraft to a halt on the runway. Once V1 is reached, the aircraft has sufficient speed to become airborne, and there is usually not enough runway left to safely stop if an abort is initiated.

By understanding this specific aspect of takeoff, pilots can better gauge the appropriate action to take when faced with potential issues during this crucial phase of flight. Other options presented do not accurately capture the role of V1 and are related to different phases or requirements of flight operations.